The present invention relates to an improved method for constructing a rotor for a fluid pump. Rotary fluid pumps are widely used in industrial applications; however, due to their weight there has been a longstanding effort to develop a lightweight rotary fluid pump that is efficient, durable and readily manufactured. In addition, for automotive and transportation applications there is an existing need for lightweight rotary pumps as means for saving energy.
The rotor of such a pump takes up a significant proportion of the inner volume of the pump, and making the rotor lighter in weight significantly improves the performance of the pump. The rotor is, however, subjected to significant stress during operation and any weight savings must also take into account the fact that the rotor must be strong as well as light.